The invention relates to a contact-making system for wire connections on electronic components in semiconductor connection technology, consisting of a contact-making device having a capillary tube arranged thereon for guiding a bonding wire, and having an electrode, which is allocated in a stationary manner or such that it can pivot into a head piece of the capillary tube, for producing a spark transfer, which is directed onto a bonding-wire endpiece which projects from the head piece, for melting the bonding-wire endpiece to form a bonding-wire sphere which can be welded to the respective component by pressure.
For the wire connection, which makes contact by means of ultrasound, of circuits to electronic components, a device is known (U.S. Pat. No. 4,586,642) in which, by means of a contact-making device which is supported such that it can pivot about an axis and is constructed as an energy transducer, a bonding wire which is guided through a capillary tube and is guided out of the capillary tube by means of an endpiece is melted by sparks and in this case is formed into a bonding-wire sphere, for example the bonding-wire sphere, which corresponds to approximately 2.5 times the wire diameter, being pressed onto a connecting surface (pad) of a semiconductor component (semiconductor device) which is known per se, and being welded (bonded).
In order to produce electrical sparks for forming the bonding-wire sphere, it is known for either an electrode which can be pivoted with respect to the capillary tube or a stationary electrode to be allocated to the head piece of the capillary tube. The wire end, which is guided centrally through the capillary tube and projects from the head piece, is melted to form a sphere by means of a spark transfer which is produced between the electrode and the wire.
In the case of the electrode which can be pivoted in, the spark is directed essentially from underneath onto the bonding-wire endpiece, this method on the one hand being dependent on an increased time requirement for the pivoting-in process and on the other hand the necessary mechanical means being subject to undesirable wear, taking into account the highly-dynamic movement sequences, and the exact formation of the bonding-wire sphere thus no longer being ensured after a relatively short operating time.
In the case of the stationary electrode, the spark is directed laterally onto the bonding-wire end-piece, this method leading to the bonding-wire sphere being formed on the bonding-wire endpiece eccentrically with respect to the symmetry axis of the bonding wire which is guided in the capillary tube, as a result of the force of the spark acting on the wire end, and it hence not being possible to maintain the required bonding accuracy.